First Embryonic Stem Cells Cloned From Adults

For the first time, scientists have successfully grown stem cells from adults using cloning techniques.

This development, published in Thursday’s online edition of the journal Cell Stem Cell, brings scientists closer to developing patient-specific lines of cells that can be used to treat medical ailments.

Guest

There's big news in the world of cloning. And to understand why, first, a little history lesson. You may recall it was back in 1996 that Scottish scientists took the nuclear the DNA from the cell of an adult sheep and put it into the egg of another sheep. That egg was then implanted into the womb of a third sheep, and Dolly was born, the world's first cloned of a mammal. Ever since Dolly's birth, scientists have been trying to replicate this technique for humans, not with the hope of producing new human beings but in an attempt to produce stem cells for medical use.

Last year, researchers successfully cloned a human embryo capable of producing stem cells. But now, another team has taken the technology a significant step further. They've created stem cells from adult human skin cells. NPR science correspondent Richard Harris joins us to discuss this discovery. Richard, great to talk to you.

RICHARD HARRIS, BYLINE: Nice to talk to you, Meghna.

CHAKRABARTI: So, first, walk us through this discovery. What exactly did the scientists accomplished?

HARRIS: Well, they repeated what I would consider the core of the Dolly experiment, that is they took DNA from the skin cells of two adult men and they put that DNA into human eggs. And after - that is after the human's - the egg's DNA had been removed. Then they coaxed those cells to divide and divide, so it turns into a state that looks a lot like an embryo. Then those embryo-like cells - turns out they can just keep dividing forever and ever. But the key is they can also be coaxed into becoming other types of cells. So you can take a little bit out of that and, say, grow a whole bunch of nerve cells. Or you can take others out and grow kidney cells and so on. And so, basically, it becomes a starting point for a lot of exciting potential medical uses.

CHAKRABARTI: OK. So it's very much like the technique that was used to make Dolly, but it sounds like it's even more versatile.

HARRIS: Yeah. It's quite similar in concept. Of course, let's not forget, though, that the huge difference is that in the experiment with Dolly, they didn't just - with Dolly, they actually attempted to implant their embryo into the other sheep, right? And this was not the idea of this experiment. So they stopped at the embryo stage. They didn't keep going on to try to clone a whole person. So, but - and obviously, many details of this experiment are different because, you know, scientists have been trying to do this for many, many years ever since Dolly, really. And it's taken a long time to tweak the recipe just enough to figure out the right conditions to make this happen.

CHAKRABARTI: Right. And it seems like one of the most exciting parts is that they used - the original cellular material they used was from adult skin cells. Now, why is that important, that the sample came from adults?

HARRIS: Well, that is an important advance because some scientists argue that, basically, the adult cells can be used - they're more useful in medicine than the infant cells. And I might add that actually before this experiment was done, there's been a long history of trials and errors. And the success with the infant cells last year is - was sort of the crowning achievement of, you know, all of these years they're trying to make this work.

The most - infamous case of this was a guy named Woo-suk Hwang in Korea who claimed he did this about a decade ago. But actually, nobody could reproduce his results, and he ultimately was accused of actually fabricating them. So that led to a whole decade of frustration before the advance last fall with the infant cells and now the adult cells. So we pretty much now come full circle and done the Dolly experiment, at least up to making the embryo.

CHAKRABARTI: OK. So regarding this new technique and this new breakthrough that we're discussing, how will these particular stem cells be useful in treating diseases, for example?

HARRIS: Well, that remains to be seen. And for one thing, it turns out that there's another way to produce these stem cells without using the egg injection method. And researchers have actually been using those other stem cells to do things like grow nerve cells, and they've been implanting them in the eyes of people who have vision problems and so on. So there are a lot of possibilities of what you could do with these cells.

But in the first place, no one's sure that the Dolly method is going to be better than the existing method that's already being tried out a little bit in human beings. But, I mean, think about replacing broken heart tissue or these vision problems or so on. And so, there's a lot of possibilities here.

CHAKRABARTI: Hmm. And, Richard, just to be clear because I want to be sure I've got this straight. The scientists were able to coax the cells - the stem cells to form different sorts of tissues, at least in the early stages, right?

HARRIS: That's right. And I don't think they've done the entire symphony of possibilities, but people have been here before and they're pretty confident that once you get to this stage, they pretty much know the recipes for coaxing it into other sorts of cells.

CHAKRABARTI: OK. So that's exciting. But on the other hand, I heard you say a little earlier that the intention of this experiment was not to create an actual, viable, you know, human embryo. But that's, of course, we were talking about Dolly earlier. Dolly was an embryo that went to - went on to become a sheep...

HARRIS: That's right.

CHAKRABARTI: ...a viable, living organism. Is that even possible with this new technique?

HARRIS: Well, we don't know. We are in principle closer to cloning a human being with this technique. And theoretically if one of these synthetic embryos is implanted into a womb, there's at least some chance is could develop into an individual who's genetically nearly identical to one of the men who donated their DNA. However, that said, there's a huge risk that if anyone actually tried this, the resulting person would actually any number of very serious health issues, that chances of getting a really healthy person out of a process like this seem to be very small. And so, that's just one reason why even attempting that is considered an unethical step.

CHAKRABARTI: OK. Well, so that actually pre-empts the next question I was going to ask you, but I'm going to ask it anyway because we can't have a conversation about embryonic stem cell research or just even synthetic embryonic stem cell research without talking about all the attendant controversy that goes along with it. Does this new technique is - does it - does the technique obviate the controversy? Or are people still concerned about the fact that if indeed it could go on to become a viable embryo, that we have the same problems all over again?

HARRIS: Well, we certainly do have the same problems all over again, and there are many layers of ethical issues. Let's step back a second and remember that some people considered the manufactured embryo in this research to be a potential human life. And even if in these experiments it remains a ball of cells, people still find that in itself objectionable - some people do - as unethical. Not everyone, of course, but that's issue one. The other issue is the potential cloning of a human being. Not only is it an ethical question because you might not produce a healthy person, but just the whole idea is repugnant that you could produce somebody by, you know, essentially a genetic duplicate of yourself as opposed to, you know, doing reproduction the traditional way.

And of course let's remember that it's not just a person's genes, but also your environment that shapes who you'll be. So you're never even going to be able to make a complete true clone of yourself in any event. But these whole ideas are - understandably make people queasy and very uncomfortable, and many people consider them unethical. That said, it is interesting that there is no federal law against doing this. And while some states have banned it and professional scientific communities and society say no, no, no, this is unethical, don't do it, it could still be done by a private lab somewhere. It could be attempted, at least.

CHAKRABARTI: Well, Richard, we've got about 20 seconds to go here. But what window does this give us on possible next steps in stem cell research?

HARRIS: Well, there are many different directions, and I think part of the intrigue here is nobody really knows what's going to be the big payoff. And there are many avenues to pursue, and people are doing all sorts of - taking all sorts of tries. So we'll have - you'll have to ask me back in a while and we can maybe answer that question more fully.